Known from WO 2005/014461 A1 is an elevator with two elevator cars, wherein the two elevator cars are mutually coupled in such manner that they are movable together in an elevator hoistway. Therein, through movement of at least one elevator car in relation to the other elevator car, a vertical distance between the two elevator cars can be adjusted. Serving this purpose is an adjusting rope, one end of the adjusting rope being fastened to the hoistway floor. At the other end of the adjusting rope, a counterweight hangs. Further, the adjusting rope is passed over a traction sheave of an adjusting drive, which comprises an elevator machine. This elevator machine is provided in addition to a further elevator machine, wherein the further elevator machine serves to move the entire arrangement with the two elevator cars through the elevator hoistway.
The elevator system which is known from WO 2005/014461 A1 has the disadvantage that, effectively, two complete arrangements with elevator machines and counterweights, as well as the related necessary diverter pulleys, are required, in order, firstly, to enable the joint movement of the two elevator cars through the elevator hoistway and, secondly, to realize the displacement mechanism for adjustment of the distance between the two elevator cars. Therein, the elevator machine, which enables the movement of the two elevator cars through the hoistway, must be so powerful that it alone can move the double-decker arrangement with the two elevator cars. Further, the drive machine that is provided for changing the distance must be sufficiently powerful to assure the mutual relative movement of the two elevator cars also under unfavorable loading conditions of the two elevator cars. The relevant components, including the suspension means, or ropes, respectively, must also be designed for a correspondingly high performance capability. The overall result is hence a high outlay, a large space requirement and, associated therewith, high costs for the realization.